Edited by Ho Dinh Hai Long An - Vietnam Updated: 3/4/2015
1- Introduction to the Order Cucurbitales
1.1- Overview The Cucurbitales are an order of flowering plants, included in the rosid group of dicotyledons. This order mostly belongs to tropical areas, with limited presence in subtropic and temperate regions. The order includes shrubs and trees, together with many herbs and climbers. One major characteristic of the Cucurbitales is the presence of unisexual flowers, mostly pentacyclic, with thick pointed petals (whenever present). The pollination is usually performed by insects, but wind pollination is also present (in Coriariaceae and Datiscaceae). The patterns of speciation in the Cucurbitales are diversified in a high number of species. They have a pantropical distribution with centers of diversity in Africa, South America, and Southeast Asia. The Cucurbitales comprise the families: Apodanthaceae, Anisophylleaceae, Begoniaceae, Coriariaceae, Corynocarpaceae, Cucurbitaceae, Tetramelaceae, and Datiscaceae.
1.2- Classification Under theCronquist system, the familiesBegoniaceae,Cucurbitaceae, andDatiscaceae were placed in the orderViolales, within the subclass Dilleniidae, with the Tetramelaceae subsumed into the Datiscaceae.Corynocarpaceaewas placed in orderCelastrales, and Anisophylleaceaein orderRosales, both under subclass Rosidae.Coriariaceaewas placed inRanunculaceae, subclass Magnoliidae.Apodanthaceaewas not recognised as a family, its genera being assigned to another parasitic plant family, theRafflesiaceae. Before modern DNA-molecular classifications, some Cucurbitales species were assigned to orders as diverse asRanunculales, Malpighiales,Violales, andRafflesiales. Early molecular studies revealed several surprises, such as the nonmonophyly of the traditionalDatiscaceae, includingTetramelesandOctomeles, but the exact relationships among the families remain unclear.The lack of knowledge about the order in general is due to many species being found in countries with limited economic means or unstable political environments, factors unsuitable for plant collection and detailed study. Thus the vast majority of species remain poorly determined, and a future increase in the number of species is expected. The present classification is due toAPG III (2009). The order consists of roughly 2600 species in eight families. The largest families are Begoniaceae (begonia family) with around 1500 species and Cucurbitaceae (gourd family) with around 900 species. These two families include the only economically important plants. Specifically, the Cucurbitaceae (gourd family) include some food species, such as squash, pumpkin (both from Cucurbita), melons including watermelon (Citrullus vulgaris), and cucumber (Cucumis). The Begoniaceae are known for their horticultural species, of which there are over 130 with many more varieties.
2.1- Family Apodanthaceae + Overview The familyApodanthaceaecomprises about 10 species ofendoparasiticherbs. They live in the branches or stems of their hosts (as filaments similar to a fungalmycelium), emerging only to flower and fruit. The plants produce no green parts and do not carry out any photosynthesis (that is, they areholoparasitic). Mitochondrial and nuclear DNA sequences confidently place the Apodanthaceae in the Cucurbitales, where they also fit well in terms of their flower morphology. + Genera There are three genera: Apodanthes Berlinianche Pilostyles A third genus name that is sometimes erroneously listed was never validly published.
2.2- Family Anisophylleaceae + Overview Anisophylleaceaeare a small family with four genera, in the orderCucurbitales, according to the APG II. However, it is more isolated from the other suprafamilalcladesin this order, while it shows some similarities in flower morphology with the genus Ceratopetalum(familyCunoniaceae, order Oxalidales). Several wood features of this family are more primitive than those of the other families in the order Cucurbitales. Previously, this family was categorized under its own order, Anisophylleales, byTakhtajanin 1997. It is a pantropical family of shrubs and medium-sized to fairly large trees, occurring in wet, tropical forests and swamps of America, Africa and Asia. The palmately veinedleaveshave a rather leathery texture, entire margins, and are often asymmetrical at the base. They have minute stipules or simply lack them. They are alternate; spiral, or distichous, or four-ranked (such as inAnisophyllea). The paired leaves may be different in size or shape. The smallflowersare regular and trimerousto pentamerous. They are usually aggregated in axillaryracemesorpanicles. The flower type varies considerably, most are monoecious, exceptCombretocarpus; which is hermaphrodite, having perfect flowers. The inferior, tri- or quadrilocularovarydevelops into adrupeor asamara(as in Combretocarpus) with usually one seed, but with three or four seeds inPoga. + Genera (According to the APG II) AnisophylleaR.Br.exSabine CombretocarpusHook.f. PogaPierre PolygonanthusDucke
2.3- Family Begoniaceae (begonia family) + Overview Begoniaceaeis a family offlowering plantswith about 1400 species occurring in the subtropics and tropics of both theNew WorldandOld World.All but one of the species are in the genusBegonia. The only other genus in the family,Hillebrandia, isendemicto theHawaiian Islandsand has a single species.Phylogenetic work supportsHillebrandiaas the sister taxon to the rest of the family.The genusSymbegoniawas reduced to a section ofBegoniain 2003, as molecular phylogenies had shown it to be derived from within that genus.Members of the genus Begoniaare well-known and popularhouseplants. + Genera Begonia Hillebrandia
2.4- Family Coriariaceae + Overview The Coriariaceae has been placed within the Cucurbitales (APG, 1998).Coriariahas between 5 and 20 species depending on the particular classification (Yokoyamaet al., 2000). The genus has a remarkable geographic distribution. It is found in the Mediterranean, Southeast Asia, Central and South America, and the Pacific islands of New Zealand and Papua New Guinea (Fig. 2; Skog, 1972). This geographic disjunction has led to several hypotheses concerning its origin and diversification. Yokoyama et al. (2000) found that the basal members of the genus are found in Asia and Central America, suggesting that the origin of genus was in either Eurasia or North America. The authors further suggested that the genus originated some 60 Mybp, far older than an estimate of 5-11 Mybp based on fossil evidence. + Genera The Famil Coriariaceae has only one genus Coriaria. Coriariais the sole genus in the family Coriariaceae.described as a genus by Linnaeus in 1753.It includessubshrubs,shrubsand smalltrees, with a widespread butdisjunct distributionacross warm temperate regions of the world, occurring as far apart as theMediterranean region, southern and easternAsia,New Zealand (where some are alpine species), thePacific Oceanislands, andCentralandSouth America. Species of genus Coriaria. Coriaria angustissima-New Zealand (South I+Stewart I) Coriaria arborea-New Zealand (South I,North I, Chatham Is, Kermadec Is) Coriaria duthiei- W Himalayas (N Pakistan + Kashmir, N India) Coriaria japonica- Japan, Taiwan Coriaria kingiana-New ZealandNorth I Coriaria kweichovensis- S China, Himalayas Coriaria lurida- New Zealand(South I,North I) Coriaria myrtifolia- Spain, France, Italy, Algeria, Morocco, Greece, Tunisia Coriaria napalensis - Himalayas Coriaria plumosa-New Zealand (South I,North I) Coriaria pottsiana-New ZealandNorth I Coriaria pteridoides-New ZealandNorth I Coriaria ruscifolia-Latin Americafrom C Mexicoto S Argentina+ S Chile;New Guinea,New Zealand, islands of SPacific Coriaria × sarlurida-New Zealand Coriaria × sarmangusta-New Zealand Coriaria terminalis- Sichuan,Tibet, Nepal,Sikkim, Bhutan
2.6- Family Cucurbitaceae (gourd family) + Overview The Cucurbitaceae, also cucurbits, are a plantfamily, sometimes called the gourd family, consisting of around a hundred genera. The plants in this family are grown around the tropics and in temperate areas, where those with edible fruits were among the earliest cultivated plants both in the Old and New Worlds. The Cucurbitaceae family ranks among the highest of plant families for number and percentage of species used as human food. Most of the plants in this family are annualvines, but some are woody lianas, thorny shrubs, or trees (Dendrosicyos). Many species have large, yellow or white flowers. The stems are hairy and pentangular. Tendrils are present at 90° to the leaf petioles at nodes. Leaves are exstipulate alternate simple palmately lobed or palmately compound. The flowers are unisexual, with male and female flowers on different plants (dioecious) or on the same plant (monoecious). The female flowers have inferior ovaries. The fruit is often a kind of modified berry called a pepo. + Important genera The Cucurbitaceae consist of 98 proposed genera with 975 species, mainly in regions tropical and subtropical. The most important genera of the gourd family are: Cucurbita - squash, pumpkin, zucchini, some gourds Lagenaria - mostly inedible gourds Citrullus - watermelon (C. lanatus, C. colocynthis) and others Cucumis - cucumber (C. sativus), various melons Luffa - common name also luffa
2.7- Family Datiscaceae + Overview The Family Datiscaceae currently is classified in the order Cucurbitales (APG, 1998). Datiscaceae, family of the squash order (Cucurbitales) of flowering plants, with one genus: Datisca. Datiscaceae are slim herbaceous plants, with alternate and pennate leaves. + Species of the genus Datisca The genus Datisca contains two species; one from Asia and one from North America. - The species Datisca cannabina, which is found from the Mediterranean eastward to Central Asia, is a hemplike plant, 2 metres (7 feet) high, that has leaves with three to seven alternate, toothed leaflets. The female plants have sprays of yellow flowers, and a yellow dye is derived from the roots. - The species Durango root (Dastisca glomerata), native in coastal ranges of southwestern North America, grows to 1.25 metres (4 feet) tall and has deeply cut leaflets and inconspicuous flowers.
2.8- Family Tetramelaceae + Overview TheTetramelaceaeare a family ofplantformerly classed in theDatiscaceaefamily. It is a small family of the squash order (Cucurbitales) of flowering plants containing two genera, each with one species. + Genera - Octomelesis amonotypicgenus ofplantin family Tetramelaceae. The sole species isOctomeles sumatrana. Octomeles sumatranais found inBrunei, Indonesia,Malaysia,Papua New Guinea, the Philippines, and theSolomon Islands. - Tetramelesis amonotypicgenus ofplantin family Tetramelaceae. The sole species isTetrameles nudiflora. It is a large deciduous tree found across southern Asia from India through southeast Asia, Malesia and into northern Australia.